Pierre Bayle (French: [bɛl]; 18 November 1647 – 28 December 1706) was a French philosopher and writer best known for his seminal work the Historical and Critical Dictionary, published beginning in 1697.

Bayle was a Protestant. As a forerunner of the Encyclopedists and an advocate of the principle of the toleration of divergent beliefs, his works subsequently influenced the development of the Enlightenment.

There he became acquainted with the teachings of René Descartes. He returned to France and went to Paris, where for some years he worked under the name of Bèle as a tutor for various families. In 1675 he was appointed to the chair of philosophy at the Protestant Academy of Sedan. In 1681 the university at Sedan was suppressed by the government in action against Protestants.

Just before that event, Bayle had fled to the Dutch Republic, where he almost immediately was appointed professor of philosophy and history at the École Illustre in Rotterdam. He taught for many years, but became embroiled in a long internal quarrel in the college. It resulted in Bayle being deprived of his chair in 1693.

Bayle remained in Rotterdam until his death on 28 December 1706. He was buried there in the Waalse Kerk, where Jurieu would also be buried, seven years later.

At Rotterdam, Bayle published his famous Pensées diverses sur la comète de 1680 in 1682, as well as his critique of Louis Maimbourg's work on the history of Calvinism. The reputation achieved by this critique stirred the envy of Pierre Jurieu, Bayle's Calvinist colleague of both Sedan and Rotterdam, who had written a book on the same subject.

Between 1684 and 1687, Bayle published his Nouvelles de la république des lettres, a journal of literary criticism. In 1686, Bayle published the first two volumes of Philosophical Commentary, an early plea for toleration in religious matters. This was followed by volumes three and four in 1687 and 1688.

In 1690 there appeared a work entitled Avis important aux refugies, which Jurieu attributed to Bayle, whom he attacked with great animosity. After losing his chair, Bayle engaged in the preparation of his massive Dictionnaire Historique et Critique (Historical and Critical Dictionary), which effectively constituted one of the first encyclopaedias (before the term had come into wide circulation) of ideas and their originators. In the Dictionary, Bayle expressed his view that much that was considered to be "truth" was actually just opinion, and that gullibility and stubbornness were prevalent. The Dictionary would remain an important scholarly work for several generations after its publication.[2]

The remaining years of Bayle's life were devoted to miscellaneous writings. In many cases, he was responding to criticisms made of his Dictionary.

The Nouvelles de la république des lettres was the first thorough-going attempt to popularise literature, and it was eminently successful. His multi-volume Historical and Critical Dictionary constitutes Bayle's masterpiece. The English translation of The Dictionary, by Bayle's fellow Huguenot exile Pierre des Maizeaux, was identified by U.S. President Thomas Jefferson to be among the one hundred foundational texts to form the first collection of the Library of Congress.

In his Dictionnaire historique and critique and Commentaire Philosophique, he advanced arguments for religious toleration.

Bayle rejected the use of scripture to justify coercion and violence: "One must transcribe almost the whole New Testament to collect all the Proofs it affords us of that Gentleness and Long-suffering, which constitute the distinguishing and essential Character of the Gospel." He did not regard toleration as a danger to the state, but to the contrary:

"If the Multiplicity of Religions prejudices the State, it proceeds from their not bearing with one another but on the contrary endeavouring each to crush and destroy the other by methods of Persecution. In a word, all the Mischief arises not from Toleration, but from the want of it."[3]

Richard Popkin has advanced the view that Pierre Bayle was a superskeptic who used the Historical and Critical Dictionary as a way of critiquing all prior known theories and philosophies. In Bayle's view, humans are inherently incapable of achieving true knowledge. Because of the limitations of human reason, we must adhere instead to our conscience alone. Bayle was critical of such rationalists as Descartes, Hobbes, Spinoza, Malebranche and Leibniz.[4] Perhaps one of the most famous quotes of Bayle sums up his view of human intellect fairly well in Popkin's opinion:

"It [reason] is a guide that leads one astray; and philosophy can be compared to some powders that are so corrosive that, after they have eaten away the infected flesh of a wound, they then devour the living flesh, rot the bones, and penetrate to the very marrow. Philosophy at first refutes errors. But if it is not stopped at this point, it goes on to attack truths. And when it is left on its own, it goes so far that it no longer knows where it is and can find no stopping place." [5]